Declining woodland birds in North America: Should we blame Bambi?

Abstract

Aim: We evaluate the possible link between increasing deer populations and declines in woodland birds. Location: North American continent. Methods: We used a group of 73 forest bird species that had been tested for their sensitivity to the impact of overabundant deer on forest understory. We used Breeding Bird Survey data to assess population trends for these 73 songbird species between 1966 and 2009, a period of marked continent-wide increases in white-tailed (Odocoileus virginianus) and mule or black-tailed (Odocoileus hemionus) deer. Results: We show a continent-wide link between increase in deer populations and declines in forest-songbird species-dependent on understory for nesting and/or foraging. Main conclusions: Increasing deer populations may actually play an important and underestimated role in the decline of North American songbirds. © 2012 Blackwell Publishing Ltd.